Tag Archives: Apple

ABC of the Sea released!

About a week ago ABC of the Sea was accepted by Apple for inclusion in the App Store! It’s a universal app that will work on all recent iOS devices but it really is visually more exciting on the iPad.

Obligatory plug: It’s only 99¢ (or other local denomination)! Go buy it!

ABC of the Sea is a children-focused animated book featuring 26 pages of hand-drawn marine life. The illustrations were originally produced by my wife many years ago but never published. Our own child can now read and a print of the book surfaced which she thoroughly enjoyed. We then had the idea to turn it into an iPad application. Each page has been carefully, but subtly animated in a fashion largely consistent with how the creature (or plant) behaves in its natural habitat, though some artistic license has been taken if the real-life movements would be virtually undetectable. Continue reading

Using an RSA public key generated by OpenSSL in iOS

Apple have gone to pains to make cryptography in iOS (and MacOS in general) secure, building a layer between applications and the low-level stuff, like OpenSSL. The principle is to keep these functions in separate address space thus significantly reducing the surface area available for malicious code to find a weakness. In iOS this separation is enforced and, significantly, the documentation is sparse and terse. Public key use without also using certificates is mentioned but only in the context of using keys generated on the device. Posts on the Apple Developer forums indicate that using certificates is suggested because using public key pairs is “involved“. It turns out that the reason it’s involved is because of some odd implementation details and the aforementioned lack of documentation or useful examples.

I was developing a mechanism to verify some data that was generated outside the device with a public key. Using a simple key pair generated by OpenSSL at a command line it was very simple to create scripts in Perl and PHP to produce (and sign) and then decode (and validate) some data using this key pair. The functions to add a public or a private key to the keychain are there in iOS but they don’t work as expected. Continue reading

How to find the moon

Moon during Lunar Eclipse

The Moon

Intriguing title for a first web log post? I thought so! It’s the working title for something that, like so much that I am doing now, exists only in my head at the moment. It will be a childrens story based on a series of dialogue with my daughter on the way to school that began with:

Her: “Where are we going?”

Me: “The moon!”

Her: “Really? How do we get there?”

Continue reading